NaY分子筛Lewis酸促进甲醇经亚硝酸甲酯分解制二甲氧基甲烷  

Lewis Acid in NaY Zeolite High Selectively Catalyze Methanol to Dimethoxymethane via Methyl Nitrite

作　　者：江辉波 林姗姗 徐玉平 孙径[2] 徐忠宁[2] 郭国聪[2] Jiang Huibo;Lin Shanshan;Xu Yuping;Sun Jing;Xu Zhongning;Guo Guocong(College of Chemical Engineering,Fuzhou University,Fuzhou 350116,China;State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China)

机构地区：[1]福州大学石油化工学院,福州350116 [2]中国科学院福建物质结构研究所结构化学国家重点实验室,福州350002

出　　处：《化学学报》2022年第4期438-443,共6页Acta Chimica Sinica

基　　金：国家重点研发计划项目(Nos.2021YFB3801604,2017YFA0206802,2017YFA0700103,2018YFA0704500);国家自然科学基金委员会面上项目(No.22172171)资助。

摘　　要：二甲氧基甲烷(Dimethoxymethane,DMM)作为一种基础有机化学品,在树脂、溶剂、燃料等领域具有广泛用途.传统合成方法采用甲醇甲醛缩合,反应效率比较低.亚硝酸甲酯(CH3ONO)是一种性质活泼的气体,可由甲醇、O_(2)、NO在无需催化剂的条件下获得,其反应活性比甲醇高很多.通过亚硝酸甲酯在常压条件下催化分解可以高效制备DMM.本工作系统研究了不同类型分子筛的酸性对亚硝酸甲酯催化分解制备DMM的影响规律,催化活性顺序为:NaY(97%)=HY(97%)>HZSM-5(90%)>Hβ(89%)>Na ZSM-5(18%)>Naβ(6%),DMM选择性顺序为:NaY(53%)>HY(12%)=Naβ(12%)>Na ZSM-5(7%)>Hβ(4%)>HZSM-5(3%),其中NaY分子筛是一种性能优异的亚硝酸甲酯分解制备DMM的催化剂.通过X射线衍射(XRD)、比表面及孔隙度分析(BET)、扫描电子显微镜(SEM)、吡啶红外(Py-FTIR)等结构表征手段,发现分子筛的酸性位点是促进亚硝酸甲酯分解的活性中心,而Na^(+)和Al物种的Lewis酸是高选择性生成DMM的关键.本工作可为DMM提供一种新的高效合成路线.Dimethoxymethane(DMM)has wide application in resin,solvent,and fuel fields as a fundamental organic chemical.The traditional route to synthesize DMM using methanol and formaldehyde as reactants via condensation reaction has poor efficiency.Methyl nitrite(MN),which is obtained by the reaction of methanol,oxygen and nitrite monoxide without catalysts,could be used as raw material to produce DMM through catalytic decomposition.The current work systematically investigated the catalytic activity and selectivity to DMM of several molecular sieves in MN decomposition reaction.The results show that the activity trend is NaY(97%)=HY(97%)>HZSM-5(90%)>Hβ(89%)>NaZSM-5(18%)>Naβ(6%),and the DMM selectivity trend is NaY(53%)>HY(12%)=Naβ(12%)>Na ZSM-5(7%)>Hβ(4%)>HZSM-5(3%).X-ray diffraction(XRD),Brunner-Emmet-Teller measurements(BET),scanning electron microscope(SEM)and Pyridine-IR(Py-IR)experiments have been employed to reveal the structure-activity relationship of these molecular sieves.Combining the temperature-programmed desorption of CO_(2)experiments(CO_(2)-TPD)data with the evaluation results of the catalytic performance of the zeolite catalyst,the basic sites of the zeolite have no direct connection to the catalytic MN decomposition process.Meanwhile,the calcination temperature experiment of NH_(4)-zeolite and the catalytic performance test experiment of NaY-tetraethoxysilane(TEOS)further proved that the acid site played an essential role in promoting the decomposition of MN,and the results show that the Lewis acidity sites of Na^(+)and low-coordinated Al metal center are key factors to catalyze MN to DMM high selectively.We have proposed the MN decomposition mechanism.In the process of MN decomposition,there are both proton generation and proton consumption processes.Intermediates in the decomposition process are easily protonated by Br?nsted acid sites to form by-products.The Lewis acid site of zeolite is generally a low-coordinated Al metal center,which can effectively adsorb and stabilize the oxygen-containing in

关 键 词：亚硝酸甲酯 二甲氧基甲烷 分子筛 NAY LEWIS酸 

分 类 号：TQ224.4[化学工程—有机化工]